The Cessna 206 left Concord’s Buchanan Field Airport on Monday morning and crashed upside down in a marsh 31/2 miles southwest of the Napa County Airport after encountering engine trouble.

The pilot, 70 -year-old Norman Pease of Orinda, radioed Concord about 10 minutes after take-off that he had a “rough-running engine” but he wanted to try to land in Napa rather than turn around, said Ian Gregor, spokesman for the Federal Aviation Administration.

Pease and his two friends, Ottis McCain, 62, of Lafayette and Kenneth Crain, 84, of Orinda were heading north to go fishing on the Mendocino coast, said Sgt. Chris Perry of the Napa County Sheriff’s Office.